3D Lyman-alpha radiation transfer. I. Understanding Lyman-alpha line profile morphologies

By A. Verhamme, Daniel Schaerer, Antonella Maselli. 2006

167 citations recorded by the source corpus.

Using a Monte Carlo technique, we have developed a 3D lyman-alpha radiation transfer code allowing for prescribed arbitrary hydrogen density, ionisation, temperature structures, and dust distribution, and arbitrary velocity fields and UV photon sources. We have examined the lyman-alpha line profiles predicted for several simple geometrical configurations and their dependence on the main input parameters. Overall, we find line profiles reaching from doubly peaked symmetric emission to symmetric Voigt (absorption) in static configurations with increasing dust content, and asymmetric red-(blue-) shifted emission lines with a blue (red) counterpart ranging from absorption to emission (with increasing line/continuum strength) in expanding (infalling) media. The following results are of interest for the interpretation of lya profiles from galaxies. 1/ Standard lya absorption line fitting of global spectra of galaxies may lead to an underestimate of the true hydrogen column density in certain geometrical conditions. 2/ Normal (inverted) P-Cygni like lya profiles can be obtained in expanding (infalling) media from objects without any intrinsic lya emission, as a natural consequence of radiation transfer effects. 3/ The formation and the detailed shape of lya profiles resulting from expanding shells has been thoroughly revised: for sufficiently large column densities, the position of the main lya emission peak is redshifted by twice the expansion velocity.This is in excellent agreement with the observations of z~3 LBGs. This finding indicates also that large scale, fairly symmetric shell structures must be a good description for the outflows in LBGs.(shortened abstract)

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/743b0f4799d3a7bf67e9132667d86783a8b04164

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Citations in the corpus

ramses-rt: radiation hydrodynamics in the cosmological context (2013, background): “…where Doppler/redshift effects in resonant photon scattering are important, Monte Carlo schemes are the only feasible way to go – though in these cases, post-processing RT is usually sufficient (e.g. Cantalupo et al. 2005; Verhamme et al. 2006; Laursen & Sommer-Larsen 2007; Pierleoni et al. 2009).”
The GLASS-JWST Early Release Science Program. I. Survey Design and Release Plans (2022, background): “…IGM depends on the frequency of ISM-escaping photons, which is imprinted by the velocity, density, and spatial distributions of galactic gas (e.g., Verhamme et al. 2006; Wofford et al. 2013; Henry et al. 2015; Rivera-Thorsen et al. 2015; Orlitová et al. 2018; Hoag et al. 2019b; Jaskot et al.…”
Conditions for Reionizing the Universe with a Low Galaxy Ionizing Photon Escape Fraction (2019, background): “It can be an excellent tracer of a neutral IGM, as neutral H I gas resonantly scatters Lyα photons, attenuating their observable surface brightness (e.g., Miralda-Escudé and Rees 1998; Malhotra & Rhoads 2004; Santos 2004; Verhamme et al. 2006; McQuinn et al. 2007; Dijkstra 2014).”
The MUSE Hubble Ultra Deep Field Survey - VIII. Extended Lyman-α haloes around high-z star-forming galaxies (2017, background): “Looking at our sample, most of our Lyα spectra show a single asymmetric line, as expected for Lyα scattering processes in outflowing media (Verhamme et al. 2006; Dijkstra & Kramer 2012; Yang et al. 2016).”
PHYSICAL CONDITIONS IN A YOUNG, UNREDDENED, LOW-METALLICITY GALAXY AT HIGH REDSHIFT (2010, background): “Several recent models explore the connections between Lyα (and interstellar) line profiles and the kinematics of the gas (e.g. Verhamme et al. 2006, 2008; Steidel et al. 2010).”